Best family cell phone plan?

Since we a moving back to the States next month, we will need to get new cell phones. When we left, we had Sprint and were happy with that. I've also worked in telecom and have spent time consulting with all the wireless carries (so I'm familur with the technical differencs between GSM and CDMA). Looking for everyone's experiences with family plans. Here is what we are looking at:- I want an iphone- Mrs wants either a BlackBerry or Android device with keyboard- 2 daughters are now at an age where they will need cell phones also- I travel for a living so pre-paid won't work for me but it is an option for everyone else in the familyI was either thinking a family plan from Sprint or just getting the all you can eat plan from Sprint and getting Virgin Mobile prepaid for everyone else.How many minutes do you guys use as a family?